More than two centuries after a shipwreck brought non-native rats to a remote Alaskan island, removing the invasive rodents has led to a rapid recovery of wildlife across the 6,869-acre island in the Aleutian archipelago. According to monitoring reports and press releases from the United States Fish and Wildlife Service (USFWS) and the National Wildlife Refuge System, native bird populations on Hawadax Island increased by 200 per cent or more within just two years of the rat removal. Seabirds that had disappeared from the island have also started returning to its rocky cliffs to nest. The island, once known as Rat Island, got its invasive rat population around 1780 after a Japanese ship ran aground on its coast. The surviving Norway rats (Rattus norvegicus) multiplied and began feeding on bird eggs, chicks and adult birds.Native island species had evolved without land-based mammalian predators. As a result, ground-nesting and burrowing birds had few defences against the rats. Their populations fell sharply as the infestation spread across the island. In autumn 2008, the USFWS worked with conservation groups, including The Nature Conservancy and Island Conservation, to begin a major rat eradication campaign across the 10-square-mile island. Specialist teams used helicopters to spread rodenticide bait across the island according to a carefully planned digital grid. The operation successfully removed the rats. After several years of monitoring to confirm that no rodents had survived, the USFWS officially declared the island rat-free.
Native birds make a rapid comeback
Wildlife surveys after the eradication showed quick changes among ground-nesting and shorebird populations. Glaucous-winged gulls, song sparrows, rock sandpipers and black oystercatchers all increased in number. Biologists recorded a three-fold increase in glaucous-winged gull nests within two years of the operation. Surveys also found nesting tufted puffins and storm-petrels returning to the island. These birds had been almost completely wiped out during the years of rat infestation. Stacey Buckelew of Island Conservation described the dramatic change she saw after the rats were removed. “When I first landed on what was Rat Island in 2007, it was an eerily silent place,” Buckelew said in statements recorded by the USFWS. “A typical Aleutian island is teeming with wildlife, swirling with noisy, pungent birds. Not this place. It was crisscrossed with rat trails, littered with rat scat, scavenged bird bones, it even smelled…” During later monitoring visits, Buckelew said the island was “hardly recognizable among the cacophony of birds calling everywhere; it’s alive with bird fledglings”. “The return of bird life to Hawadax Island is an inspiring example of what we can accomplish when we work together to fix a longstanding problem,” Randy Hagenstein, Alaska state director for The Nature Conservancy, said in USFWS press materials.
Island gets its traditional name back
The ecological recovery also led to the island getting back its traditional name. In May 2012, after a proposal from the Aleutian Pribilof Islands Association, the U.S. Board on Geographic Names officially changed the name from Rat Island back to Hawadax Island. The Unangam Tunuu (Aleut) word Hawadax roughly means “entry” or “welcome”. Long-term research published in scientific journals, including Nature Scientific Reports, has shown that removing the rats helped restore wider natural processes on the island. As bird populations returned, they helped restore the natural balance of the island’s intertidal ecosystem. Birds also brought marine nutrients onto land through their droppings, enriching the soil and helping native plants recover. Gregg Howald, North America Region Director for Island Conservation, said the project demonstrated how effective partnerships can restore damaged ecosystems. “Hawadax Island is on a trajectory for recovery and the ecological gains we are witnessing are tremendous,” Howald said in USFWS reports. “They are a sustained testament to a conservation methodology and partnership that works.” Today, Hawadax Island is part of the Alaska Maritime National Wildlife Refuge. Its successful recovery has also made it an important example for future projects aimed at removing invasive predators from islands around the world.
